British indie thriller Beast has just had its Scottish premiere at the Glasgow Film Festival, following a hugely successful festival run around the world. The film’s a stunningly shot serial killer mystery – with two star-making turns at its centre.

It follows Moll (Jessie Buckley) a repressed woman who meets a charismatic stranger Pascal (Johnny Flynn), who may or may not be a murderer, and an intoxicating romance begins.

We sat down with director Michael Pearce and star Buckley to discuss the film.

Yahoo: Jessie, how did you prepare for your role in this film?

Jessie Buckley: Went out with a few psychopaths in my life, I’m only joking.

Yahoo: I was impressed with your performance before I met you, but now I’m amazed, you’re completely different to this character. How did you prepare?

Jessie Buckley: [laughs] Thank you, lots of different things. Michael and I spoke quite a lot about film and music before we started shooting. I spoke to victims of psychopaths and physically tried to change.

Yahoo: The physicality was really interesting. Were you thinking about animals and beasts?

Jessie Buckley: Not really, it’s more that her skin is so thin – the animal that lives there is on the surface of that transparency. So when you meet her you feel like it’s simmering right under. It was more of a feeling than ‘I’m a llama today’ [laughs] I should have done that actually, that would have been really weird.

Michael Pearce: There were quite helpful analogies involving animals, when you see a wild animal that’s been domesticated, you can see something in the back of its eyes…

Jessie Buckley: When we first met at the first audition, I’d just watched Blackfish, the documentary about killer whales, this story really reminds me of this kind of animal, somebody who’s got a danger lurking within them, the parameters of that wall are coming in tighter and tighter and they’re being tormented to react.

Then I read this book about your inner shadows and how we quench the bad things within us, the things that society’s told us are bad, they all live within us and it just takes one lancing for those things to come out. I was thinking about her in terms of working from the rawest place possible.

Yahoo: You’re going to be huge, have you thought about balancing indies with the big studio movies?

Jessie Buckley: No, I don’t really care – I just want to tell good stories with good characters.

I feel really proud to be Irish, and part of the British industry. I’m not running towards Hollywood, I just want to tell human stories about women that have complexities and layers, with foibles, that have an honesty.

Remove the sheen and tell stories that are going to provoke something, rather than being an object. So it’s not a question of studios and here, it’s about a story – and who’s involved in it.

What’s next for you Michael?

Michael Pearce: It’s a big studio film.

Jessie Buckley: And I’m not in it [laughs].

Michael Pearce: I don’t want to work with Jessie.

Jessie Buckley: You keep saying this!

Yahoo: How does it feel to have given Jessie her first lead in a feature? Obviously she’d done telly stuff before, but…

Michael Pearce: I can take a very limited amount of credit, it was the casting director Julie Harkin who had cast War & Peace brought her in front of us, and Tom Harper takes a credit as well, because we were looking at the rushes of that, he let us into the edit room.

It wasn’t like I was giving her a shot, because it was my debut – I was lucky to have her on my team. If anything, we both had a lot of stakes. It was riding on our shoulders, I’d written it and was directing it, she was on camera, everything was told through her perspective, so we had to take it seriously and test each other and push each other.

Jessie Buckley: The thing that kind of scares me about big studio movies is that intimacy is removed, I love working with people making their first feature. There’s a hunger and a rawness, a fresh take – it’s something you’re both going to explore together. You have this acclaim and success, and then if your next step is a more manicured version…

Michael Pearce: It was a great gift to us, Jessie’s commitment to it. She really went for it. Because on the first day, in the first take, she was so all-in I could feel the vibe of the crew – and maybe the other actors – witnessing her doing that, going from zero to one hundred emotionally in this one moment.

It signalled to everyone that this actress is taking it really seriously – she’s thought about it a lot, and she’s really passionate. So everyone had to up their game. There was no ‘Oh, we’re in the first week so we can spend time figuring each other out’ we were all-in within the first two hours. As a director, it was a gift of raising the barometer in terms of work, investment and passion.

Beast is in cinemas on 27 April. The Glasgow Film Festival runs from 21 February – 4 March